Tamper-revealing screw-cap for a container

Abstract: A safety screw cap indicates prior opening of a container (3) to protect consumers from prior contamination. The screw cap (1) has an annular band (2) encircling its lower end which is separated from the screw cap by a perforated line (7). The band is affixed to a fixing element (4) and the fixing element attached to the container (3) when the screw cap is screwed in place. An unattached leader portion of the band (5) can be lifted easily to peel the band from the container. As the band is peeled from the container, it is simultaneously torn from the screw cap at the perforations. Once the band is removed, the screw cap can be unscrewed and the container unsealed. Before peeling the band away, the screw cap cannot be unscrewed without causing obvious damage to the screw cap or band. In addition, the torque required to shear-separate the band from the fixing element, the fixing element from the container or the screw cap from the band is greater than that which can be applied easily by a normal adult.

Description: BACKGROUND OF THE INVENTION The present invention relates generally to screw top containers and specifically to such devices which reveal a prior opening by an alteration in their appearance when they are opened. It is relatively easy to open and reseal a screw-cap container. This presents a potential hazard to purchasers because such containers can be opened and resealed by someone other than the purchaser. Thus, container contents may be exposed and contaminated without the purchaser being aware of it. To eliminate the danger of such unapparent prior contamination of container contents, various devices have been implemented which permit a consumer to verify that a container has not been opened before the consumer purchases the product. One example is a screw cap that has a band with inward projections at the opening of the cap. When the cap is screwed onto a container, the projections on the band engage a protrusion on the container. The band breaks away from the cap at a perforated line when the cap is screwed off. Once opened, the cap and band cannot be restored to their original condition. However, the broken band only indicates a removal of the cap. Since it is necessary for the cap to lifted away from the bottle to break the cap from the band at the perforated line, any vacuum inside the container may be broken before the band breaks away. Therefore, it is virtually impossible to determine, upon quick inspection, if the vacuum has been broken without removing the cap. Since contaminants can enter once the vacuum breaks, this type of container sealing mechanism can provide no assurance that container contents are free of exposure to contaminants. Another problem with the above device is that it may be unsuitable for a large-mouth container. If the above device were applied to large-mouth container, the band portion would need to be unduly large and sturdy. The band must be sturdy to transmit torque applied to the cap via the projection on the band to the protrusion on the cap. Therefore, an excessive force would then be required to break the connection between the band and the cap and thereby open the container. Thus, this type of cap is unsuitable for a large-mouth container. Another type of tamper-revealing cap has an extended band portion which is heat-shrunk to cover the container tightly. The tight fit prevents the band from rotating when the cap is rotated. The band has a perforated line which is torn when the cap is unscrewed. A large amount of torque must be generated to remove such a cap, however. This limits its utility, especially as applied to large-mouth containers. Still another type of seal includes a ratchet mechanism on the lower end of a cap which is separated from the cap by a perforated line. The same problem of very high torque arises with this design as well. In still another design, a label is affixed over a cap and a container body. However, since the label is easy to remove, there is a great danger that the label would be intentionally removed and reaffixed after the container is opened. OBJECTS AND SUMMARY OF THE INVENTION It is an object of the present invention to provide a safety cap for a container that overcomes the drawbacks of the prior art. It is another object of the present invention to provide a safety cap for a container that indicates a prior opening. It is still another object of the present invention to provide a safety cap for a container which is easy to open. It is still another object of the present invention to provide a safety cap for a container that protects consumers against contamination of container contents. It is still another object of the present invention to provide a safety cap for a container that can be replaced after opening. According to the invention there is provided a tamper-revealing container, comprising: a screw cap threadable onto a container body having a wall and a mouth, substantially covered by said screw cap when said screw cap is threaded onto said container body; an annular band attached to the lower end of said screw cap and at least partially surrounding said container body; said annular band attached to said screw cap with a first attachment strength requiring a first torque to separate said screw cap from said annular band by rotating said screw cap relative to said annular band; a fixing element between said annular band and said wall; said fixing element engageable on one side of said fixing element with said wall such that a second torque is required to rotate said fixing element relative to said wall by rotating said fixing element relative to said container body; said fixing element engageable on another side of said fixing element with said annular band such that a third torque is required to rotate said annular band relative to said fixing member by rotating said annular band relative to said fixing element; said annular band being peelable from said screw cap, and detachable thereby, from said screw cap and said wall; said first torque being greater than either of said second and third torques. According to an embodiment of the invention said fixing element is attached to said annular band such that said fixing element peels away from said container body, with said annular band, as said annular band is peeled. According to an embodiment of the invention said first torque is substantially greater than a fourth torque, in Newton-centimetres, which is equal in magnitude to a square of a diameter of said screw cap in centimetres. According to another embodiment of the invention said fixing element is engageable on said one side of said fixing element by a projection on one of said container body and said fixing element and an edge on an other of said container body and said fixing element. According to still another embodiment of the invention said fixing element is adhesively attached to said annular band and/or to said wall. According to still another embodiment of the invention said fixing element is being attached to said annular band by a means having a first peel strength, said fixing element is attached to said wall by means having a second peel strength, said first peel strength being substantially greater than said second peel strength, whereby said fixing element is peeled away from said screw cap with said annular band. According to still another embodiment of the invention said annular band is separated from a rest of said screw cap by a break line including one of a first series of perforations and a thin-walled section of said annular band and said screw cap. According to a further embodiment of the invention said fixing element includes at least two layers bonded to each other by at least one bond that has a peel strength less than a peel strength of attachment between said annular band and said fixing element and less than a peel strength of attachment between said fixing element and said wall. The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings, in which like reference numerals designate the same elements. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a from view of a screw cap according to an embodiment of the present invention. Fig. 2 is an enlarged view of a band of the screw cap of Fig. 1. Fig. 3 is a cross-sectional view, taken along line A-A' in Fig. 2, of a fixing element between the band and a container body of Fig. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to Fig. 1, a container 10 includes a container body 3 covered by a screw cap 1. All annular band 2 is connected to a lower end of screw cap 1. In the embodiment shown, annular band 2 is contiguous with, and extends from a rim of screw cap 1. A fixing element 4 is adhesively attached to annular band 2 and container body 3. Fixing element 4 connects container body 3 to annular band 2. Referring to Fig. 2, annular band 2 is separated from the lower end of screw cap 1 by a break-line 6 which includes a series of perforations 7. Annular band 2 has a weakened end portion 5 for peeling annular band 2 from container body 3. In the current embodiment, weakened end portion 5 includes another series of perforations, or a break, running across annular band 2. In addition, weakened end portion 5 is not connected to container body 3. Thus, weakened end portion 5 of annular band 2 may be lifted away from container body 3 to be gripped. Weakened end portion 5 may then be pulled and annular band 2 peeled from container body 3. As annular band 2 is peeled, annular band 2 is simultaneously torn from screw cap 1 at break-line 6 with the help of series of perforations 7. Note that various devices for permitting the detachment of annular band 2 from screw cap 1 may be employed. Concentric series of perforations 7 is only one example. Additionally, weakened end portion 5 is only one means for providing a leader or grip for pulling annular band 2 from container body 3 and screw cap 1. Referring now to Fig. 3, fixing element 4 attaches to annular band 2 on one side and to container body 3 on its other side. Fixing element 4 comprises a single layer. However, to adjust the shear required to separate annular band 2 and container body 3, a layer of separation-causing material may be incorporated within fixing element 4 to cause separation to occur within fixing element 4. It is also possible to form a multiple-layer fixing element 4 with a separation-causing material between the layers to obtain a similar result. When fixing element separates internally, part of fixing element 4 remains on container body 3 when annular band 2 is peeled from container body 3. Also, in such case, another part of fixing element 2 remains on annular band 2 when annular band 2 is peeled. Unless annular band 2 is cut and removed, screw cap 1 cannot normally be rotated by hand. Therefore, screw cap 1 cannot be removed, or the vacuum broken, without breaking annular band 2 or puncturing screw cap 1. The removal or breaking of annular band 2 reveals tampering or contamination because it cannot be reattached. Thus, the integrity of annular band 2 and/or the integrity of the connection of annular band 2 to screw cap 1 indicates whether container 10 has ever been opened. It is essential that annular band 2 be required to be separated from screw cap 1 in order to rotate screw cap 1. This is to insure that any rotation of screw cap 1 is revealed by the detachment. For this purpose, annular band 2 is attached to fixing element 4 and fixing element 4 attached, in turn, to container body 3. Thus, annular band 2 is secured to container body 3. To remove annular band 2 from container body 3, one must separate the weakest of the two interfaces. That is, the interface between annular band 2 and fixing element 4 or the interface between fixing element 4 and container body 3 must be separated. Annular band 2 must be attached to container body 3 to prevent screw cap 1 front being rotated without breaking annular band 2 from screw cap 1. If screw cap 1 could be rotated without breaking annular band 2 away from screw cap 1, and if screw cap 1 were replaced, there would be no separation between screw cap 1 and annular band 2 to reveal the opening. Thus, fixing element 4 serves to attach annular band 2 to container body 3 to prevent rotation of screw cap 1 unless annular band 2 is broken, as when screw cap 1 is removed. The application of a torque to screw cap 1 is resisted by a shear force between annular band 2 and container body 3. The shear force is transmitted from screw cap 1 to annular band 2. The shear force is then transmitted front annular band 2, to fixing element 4 and then to container body 3. Therefore, the shear force must be resisted by the interface between screw cap 1 and annular band 2, that between fixing element 4 and container body 3 and that between fixing element 4 and annular band 2. A shear strength of fixing element 4 or any of the respective interfaces can be characterized by the torque that must be applied to screw cap 1 to break fixing element 4, or shear-separate the interface. If the shear strength of the interface between fixing element 4 and annular band 2 is smaller than the shear strength of the interface between annular band 2 and screw cap 1, screw cap 1 can be rotated and opened without separating screw cap 1 from annular band 2. In other words, if the torque required to cause shear separation of fixing element 4 from annular band 2 is smaller than the torque required to break annular band 2 at break-line 6, screw cap 1 can be rotated and opened without separating screw cap 1 from annular band 2. The same is true if the torque required to cause shear separation of fixing element 4 from the wall of container body 3 is smaller than the torque required to break annular band 2 at break-line 6. In such cases, when screw cap 1 is screwed back onto container body 3, container 10 appears to be unaltered, giving no indication that it had been opened. The ability of annular band 2 to reveal prior opening of container 10 is entirely lost. Therefore, it is necessary for the shear strengths of the interface between fixing element 4 and annular band 2 and the interface between fixing element 4 and the wall of container body 3 to be greater than the shear strength of the interface between annular band 2 and screw cap 1 at break-line 6. That is: τ p < τ b and τ p < τ w where τ p is the torque required to break the connection between screw cap 1 and annular band 2, τ b is the torque required to shear-separate annular band 2 and fixing element 4 and τ w is the torque required to shear-separate fixing element 4 and container body 3. If the torque required to break break-line 6 is too small, fixing element 4 and annular band 2 may remain attached to container body 3 when screw cap 1 is removed. If screw cap 1 is then screwed back onto container body 3, the perforations of perforated line 7 may be lined up, obfuscating the prior opening. Thus, the interface between screw cap 1 and annular band 2 must be strong enough to resist being broken by application of torque to screw cap 1. Since the interface between screw cap 1 and annular band 2 must be stronger than those of the other two interfaces (i.e., inequalities (1) and (2)), the shear strengths of the other interfaces must also be strong enough to resist being broken by application of torque to screw cap 1. In other words, if the shear strengths of all the interfaces, that between screw cap 1 and annular band 2, that between annular band 2 and fixing element 4 and that between fixing element 4 and container body 3, are greater than that required to resist the torque that can be applied by an ordinary adult, screw cap 1 cannot be opened without great difficulty unless annular band 2 is first removed from screw cap 1 by peel-separation. That is: τ h < τ p , τ h < τ w and τ h < τ b where τ h is the maximum torque that a normal adult male can manually apply to screw cap 1. As described above, the present invention provides a means for peeling annular band 2 from container body 3 prior to unscrewing screw cap 1. The means permits annular band 2 to be peeled from container body 3 by lifting weakened end portion 5 of annular band 2 and pulling annular band 2 from container body 3. Annular band 2 breaks away from screw cap 1 along series of perforations 7 and peel-separates from container body 3. When annular band 2 is separated from screw cap 1, screw cap 1 can be turned and opened easily. Even if screw cap 1 is replaced, the absence of annular band 2 evidences the prior opening. For aesthetic reasons, it is desirable for fixing element 4 to remain adhered to annular band 2 and to be removed with annular band 2 as annular band 2 is peeled away from container body 3. Thus, the peel strength of the bond between fixing element 4 and container body 3 should be less than that between fixing element 4 and annular band 2. That is: P w < P b where P w is the peel strength of the interface between fixing element 4 and container body 3 and P b is the strength of the attachment between fixing element 4 and annular band 2. The total peeling force required to remove annular band 2 includes the peeling force required to break annular band 2 from screw cap 1. Thus the total peeling force P max required to be applied is: P max = P w + P p where P p is the peeling force required to break annular band 2 from screw cap 1. The magnitude of P p affects the total amount of peeling force P max required to remove annular band 2 and screw cap 1 from container body 3. However, the magnitude of P p does not determine whether fixing element 4 will remain attached to annular band 2 after annular band 2 is peeled front container wall 3. Thus, inequality (6) is sufficient to guarantee that fixing element 4 will remain attached to annular band 2 after it is removed from container body 3 and not left on container body 3. When P w is less than P b , the interface between container body 3 and fixing element 4 will separate before enough force can be applied to separate the interface between fixing element 4 and annular band 2. The force applied to break-line 6 with series of perforations 7 is transmitted to screw cap 1 alone and not to the interface between fixing element 4 and container body 3 or the interface between fixing element 4 and annular band 3. Thus, no matter how strong the connection between annular band 2 and screw cap 1, whether fixing element 4 remains attached to container wall 3 after annular band 2 is pulled with a force greater than P max will depend only on P w relative to P b . It is a simple matter to form an interface with low peel strength and high shear strength. That is, it is easy to create an interface that can be peeled by applying less force than required to overcome it by application of a shear force. It is desired for the peeling force to be much less than the upper limit of human strength and the shearing torque to be substantially greater than such limit. For example, most adhesives form bonds that are much easier to peel-separate than to shear separate. Thus, interfaces may be formed that satisfy inequalities (3), (4) and (5) and yet also satisfy: P h > P w where P w is the peeling force required to separate the interface between fixing element 4 and container body 3 and P h is the maximum force that can easily be applied by a normal adult. The peel separation of annular band 2 and screw cap 1 can similarly be made much easier than the corresponding shear separation. A series of perforations would be much easier to peel separate than to shear separate since all of the bridges between the perforations would have to be broken at once in order to shear separate the two components, but only one at a time in order peel separate them. As stated, means other than series of perforations 7 for breaking annular band 2 from screw cap 1 may be employed such as a thin section between annular band 2 and screw cap 1. In order for annular band 2 to be peel separated, it must be possible to obtain a leader to pull on. One embodiment of the present invention provides weakened end portion 5 which can be separated easily from the rest of annular band 2. As mentioned above, weakened end portion 5 of annular band 2 includes a break or a series of perforations running across annular band 2. Also, weakened end portion 5 remains unattached to container body 3 so that it can be grasped easily. Alternatively, weakened end portion 5 could be broken easily across the width of annular band 2 instead of being provided with a series of perforations. Once weakened end portion 5 is broken, it can be grasped and pulled to remove annular band 2. It is known front past experiment that the rotational torque that a normal adult can apply to it container cap, such as screw cap 1, is closely related to the diameter D of the cap. It has been confirmed that the range of torques, M' (N·cm), that an normal adult can apply to container 10 to open screw cap 1 of container 10 lies within the range satisfying equation (10): 0.4 · D 2 < M' < 1 · D 2 where D is the diameter of screw cap 1 in centimeters. It has also been confirmed by experiment that the torque M beyond that which an ordinary male adult can generate easily by hand is in the range: 1 · D 2 < M < 8 · D 2 , the lower limit being the upper limit of equation 10. Accordingly, when the maximum torque that can be applied by hand τ h satisfies equation (11), container 10 cannot be opened without removing annular band 2 thereby revealing the opening. Thus, if a torque substantially greater than 1 · D 2 would have to be applied to screw cap 1, it could be considered virtually impossible to open by hand. It is intended to be understood that inequalities (10) and (11) are not dimensionally accurate and are meant to show only a numerical relationship. Opening torque M includes a component of torque arising from the opening torque of screw cap 1 absent fixing element 4. Fixing element 4 is connected to annular band 2 and connects a wall of container body 3 to annular band 2. Fixing element 4 should be attached to the wall of container body 3 so that the torque required to detach it is smaller than that required to detach the interface between annular band 2 and fixing element 4 as described above. In addition, this torque should be greater than the torque that an ordinary adult male can apply easily by hand. Another way to provide for removal of annular band 2 from container body 3 is to provide a multiple-layer type of fixing element 4. When fixing element 4 consists of a single layer, the separable interface between fixing element 4 and the wall of container body 3 is that between the wall of container body 3 and the inward-facing surface of the single layer fixing element 4. If fixing element 4 consists of multiple layers, the separable interface between fixing element 4 and the wall of container body 3 can be the interfaces between layers of fixing element 4. In any case, the separation is a result of separating the weakest of the interfaces. Ordinarily, it is undesirable for fixing element 4 permanently to fasten annular band 2 to the wall of container body 3. However, if the separable interface lies within fixing element 4, the interface between the wall of container body 3 and fixing element 4 must be permanent. Thus, a layer of fixing element 4 may remain adhered to the wall of container body 3 after annular band 2 is removed and container 10 opened. If the adherent layer is designed appropriately, there will be no adverse effect on the appearance of opened container 10. One means for allowing fixing element 4 to be peeled easily is to not attach fixing element to either annular band 2 or container body 3. Some engaging means can be used on container body 3 and fixing element 4 to resist rotation of fixing element 4 relative to container body 3 when screw cap 1 is rotated. For example, container body 3 may have a projection (not shwon) on either container body 3 or fixing element 4 and an edge (not shown) to engage the projection on the other of container body 3 and fixing element 4. Fixing element 4 can be attached to annular band 2. Alternatively fixing element 4 may include an edge (not shown) or an projection (not shown) to engage a projection (not shown) or edge (not shown) on annular band 2. Note that fixing element 4 may encircle container body 4 or cover only a portion of container body 3. When the separable interface is that between the wall of container body 3 and fixing element 4, it is preferable that fixing element 4 be secured impermanently by an adhesive agent. This is because permanent adhesion by a strong adhesive agent prevents annular band 2 from being separated from container body 3, in turn preventing connecting portion 6 from being broken by peeling annular band 2 away from screw cap 1. It is preferable for the adhesive agent to adhere impermanently to the wall of container body 3, but very tenaciously to annular band 2. This will insure that the adhesive is removed together with fixing element 4 and annular band 2 and not remain on container body 3. This prevents the adhesive from marring the appearance of container body 3 after screw cap 1 is removed. A hot-melt type of adhesive of the same material as annular band 2 may be used to achieve this result and is desirable. If no fixing element 4 lies between weakened end portion 5 and the wall of container body 3, peeling annular band 2 from container body 3 will be easier. This is because weakened end portion 5 is unattached and thereby easier to lift away from container body 3. On the other hand, it is preferable for fixing element 4 to secure an end of annular band 2 opposite weakened end portion 5 to container body 3. Opening Test A screw cap 1 having annular band 2 and series of perforations 7 as shown in Fig. 2 was made of polypropylene. A polypropylene hot-melt adhesive agent was applied beforehand to part of the inside of annular band 2. Annular band 2 and screw cap 1 were screwed onto a threaded cylinder similar to that of container body 3. The cylinder opening had an outer diameter of 70 mm, a diameter suitable for container body 3. The temperature of the cylinder was raised to about 110 ÛCby high frequency heating from the outside of annular band 2 causing the hot-melt adhesive agent to fuse. The cylinder and annular band 2 were then cooled. The cylinder was stood with the capped end down and a metal screw cap like screw cap 1 was screwed twice around the other end of the cylinder. A vacuum pump pulled a vacuum of approximately 60 cm Hg to simulate sealed container 10 with a vacuum inside. The cylinder was connected to a TNK-120 torque meter (Shinpo Kogyo Co.), and polypropylene screw cap 1 unscrewed. Torque was measured as torque, applied to screw cap 1, was increased until screw cap 1 was unsealed, thereby breaking the vacuum. When screw cap 1 was rotated directly without pulling annular band 2 off, the vacuum-breaking torque was more than 90 N·cm because the torque had to overcome and break the hot-melt adhesive portion to rotate screw cap 1. When annular band 2 was peeled off beforehand, the torque required to unseal screw cap 1 and break the vacuum was 30 to 35 N·cm. The shape of screw cap 1 before and after opening was greatly altered by removing annular band 2, which was a satisfactory indication that screw cap 1 had been unsealed. Comparative Example Screw cap 1 having annular band 2 and series of perforations 7 as shown in Fig. 2 was made of polypropylene. Screw cap 1 had a fin-shaped projection on the inside of annular band 2. Screw cap 1 was screwed onto a threaded cylinder. The cylinder opening had an outer diameter of 70 mm. The cylinder had a ratchet-like projection to engage the fin-shaped projection. The cylinder was stood with the clipped end down and a metal cap was screwed twice around the other end of the cylinder and fastened by a vacuum fastener which pulled a vacuum of approximately 60 cm Hg to simulate sealed container 10 with a vacuum inside. The cylinder was connected to a TNK-120 torque meter (Shinpo Kogyo Co.), and polypropylene screw cap 1 unscrewed. Torque was measured as sufficient torque was applied to unseal screw cap 1, breaking the vacuum. The vacuum-breaking torque was found to be 35 to 40 kg/cm. This, it was relatively easy to unseal the cylinder without entirely removing screw cap 1 from annular band 2. Screw cap 1 could not be removed before the fin of annular band 2 caught the ratchet-like projection of the cylinder. However, screw cap 1 had to be substantially elevated by the screw in order to separate annular band 2 from screw cap 1. The fracture torque for breaking annular band 2 away from screw cap 1 was approximately 110 N · cm. This torque is too high to be normally opened by a consumer. However, because the vacuum is broken before annular band 2 is broken away from screw cap 1, this type of arrangement cannot give notice of a prior unsealing of a container.

Claims: A tamper-revealing container, comprising: a screw cap (1) threadable onto a container body (3) having a wall and a mouth, substantially covered by said screw cap (1) when said screw cap is threaded onto said container body; an annular band (2) attached to the lower end of said screw cap (1) and at least partially surrounding said container body (3); said annular band (2) attached to said screw cap (1) with a first attachment strength requiring a first torque to separate said screw cap (1) from said annular band (2) by rotating said screw cap (1) relative to said annular band (2); characterized in that a fixing element (4) is provided between said annular band (2) and said wall; in that said fixing element (4) is engageable on one side of said fixing element with said wall such that a second torque is required to rotate said fixing element (4) relative to said wall by rotating said fixing element (4) relative to said container body (3); in that said fixing element (4) is engageable on another side of said fixing element with said annular band (2) such that a third torque is required to rotate said annular band relative to said fixing member (4) by rotating said annular band relative to said fixing element; said annular band being peelable from said screw cap (1), and detachable thereby, from said screw cap (1) and said wall; and in that said first torque is greater than either of said second and third torques. A tamper-revealing container according to claim 1, characterized in that: said fixing element (4) is attached to said annular band (2) such that said fixing element (4) peels away from said container body (3), with said annular band (2), as said annular band is peeled. A tamper-revealing container according to claim 1, characterized in that: said first torque is substantially greater than a fourth torque, in Newton-centimetres, which is equal in magnitude to a square of a diameter of said screw cap in centimetres. A tamper-revealing container according to claim 1, characterized in that: said fixing element (4) is engageable on said one side of said fixing element by a projection on one of said container body (3) and said fixing element and an edge on an other of said container body and said fixing element. A tamper-revealing container according to claim 1, characterized in that: said fixing element (4) is adhesively attached to said annular band. A tamper-revealing container according to claim 1, characterized in that: said fixing element (4) is adhesively attached to said wall. A tamper-revealing container according to claim 1, characterized in that: said fixing element (4) is attached to said annular band (2) by a means having a first peel strength, said fixing element (4) being attached to said wall by means having a second peel strength and said first peel strength being substantially greater than said second peel strength, whereby said fixing element is peeled away from said screw cap with said annular band (2). A tamper-revealing container according to claim 1, characterized in that: said annular band (2) is separated from the rest of said screw cap (1) by a break line (7) including one of a first series of perforations and a thin-walled section of said annular band and said screw cap (1). A tamper-revealing container according to claim 1, characterized in that: said fixing element (4) includes at least two layers bonded to each other by at least one bond that has a peel strength less than a peel strength of attachment between said annular band (2) and said fixing element and less than a peel strength of attachment between said fixing element and said wall.

Inventors: ETOH MAKOTO, KAWAGUCHI KIYOSHI, ETOH, MAKOTO, KAWAGUCHI, KIYOSHI
Applicants: TOYO SEIKAN KAISHA LTD, TOYO SEIKAN KAISHA, LTD.
Application year: 1994
Main classification: B65D41
IPC codes: B65D41